secure_file.h

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/* Copyright (c) 2025, Oracle and/or its affiliates. */
 
#include "my_sys.h"
#include "mysql/strings/m_ctype.h"
#include "nulls.h"
 
/**
  Test a file path to determine if the path is compatible with the secure file
  path restriction.
 
  @param path null terminated character string
  @param opt_secure_file_priv secure_file_priv content
  @param system_charset_info system charset
  @param files_charset_info files charset
  @param lower_case_file_system true if lower case file system, false otherwise
 
  @retval true The path is secure
  @retval false The path isn't secure
*/
 
bool is_secure_file_path(const char *path, const char *opt_secure_file_priv,
                         CHARSET_INFO *system_charset_info,
                         CHARSET_INFO *files_charset_info,
                         bool lower_case_file_system) {
  char buff1[FN_REFLEN], buff2[FN_REFLEN];
  size_t opt_secure_file_priv_len;
  /*
    All paths are secure if opt_secure_file_priv is 0
  */
  if (!opt_secure_file_priv[0]) return true;
 
  opt_secure_file_priv_len = strlen(opt_secure_file_priv);
 
  if (strlen(path) >= FN_REFLEN) return false;
 
  if (!my_strcasecmp(system_charset_info, opt_secure_file_priv, "NULL"))
    return false;
 
  if (my_realpath(buff1, path, 0)) {
    /*
      The supplied file path might have been a file and not a directory.
    */
    const int length = (int)dirname_length(path);
    if (length >= FN_REFLEN) return false;
    memcpy(buff2, path, length);
    buff2[length] = '\0';
    if (length == 0 || my_realpath(buff1, buff2, 0)) return false;
  }
  convert_dirname(buff2, buff1, NullS);
  if (!lower_case_file_system) {
    if (strncmp(opt_secure_file_priv, buff2, opt_secure_file_priv_len))
      return false;
  } else {
    assert(opt_secure_file_priv_len < FN_REFLEN);
    buff2[opt_secure_file_priv_len] = '\0';
    if (files_charset_info->coll->strcasecmp(files_charset_info, buff2,
                                             opt_secure_file_priv))
      return false;
  }
  return true;
}